CN211348449U

CN211348449U - Solid state noise source device

Info

Publication number: CN211348449U
Application number: CN201922096573.XU
Authority: CN
Inventors: 姚常飞; 冯潇潇
Original assignee: Nanjing University of Information Science and Technology
Current assignee: Nanjing University of Information Science and Technology
Priority date: 2019-11-28
Filing date: 2019-11-28
Publication date: 2020-08-25
Anticipated expiration: 2029-11-28

Abstract

The utility model discloses a solid-state noise source device, including constant current source, microstrip low pass filter, noise diode, attenuator and waveguide-coaxial-microstrip converter of electricity connection in order, noise diode is used for producing original noise signal, and original noise signal passes through the noise power is stabilized to the attenuator, microstrip low pass filter arranges in noise diode's input is used for suppressing the leakage of noise power; the waveguide-coaxial-microstrip converter is used for converting the noise signal from the waveguide into microstrip output, and the output end of the waveguide-coaxial-microstrip converter is used as the output of the solid-state noise source device; the attenuator and the waveguide-coaxial-microstrip converter jointly coordinate the impedance matching of the circuit, and the constant current source provides a stable power supply for the device. Solid-state noise source device work in the Ka wave band, have high output, high super noise ratio, still have low standing wave coefficient simultaneously.

Description

Solid state noise source device

Technical Field

The utility model relates to a solid-state noise source especially relates to a work is at solid-state noise source device of Ka wave band.

Background

At present, noise interference in signal transmission process has become a main interference of modern radio transmission and processing link, and for this reason, the anti-noise coefficient of the device is a necessary measure. The solid-state noise source has the advantages of wide frequency band, rapid switching, low power consumption, high reliability and the like, and is commonly used for noise test in the microwave radio frequency field. With the development of modern communication technology, especially satellite communication service, in recent years, C, Ku and Ka frequency bands become common frequency bands for services such as satellite live broadcast and news collection, various devices have higher requirements on noise coefficients, most of the working frequencies of the existing noise sources are concentrated on low-frequency band and narrow-frequency band noise output, and the working frequencies of some devices to be tested cannot be met. In the subject of Zhang Yonghong et al in 2018, the frequency range of a broadband noise source researched is 22-32GHz in a K wave band; in two papers published in the journal of electronics, book and the like in 2018 and 2016, the working frequency bands of the developed noise source are only concentrated on the L/C wave band. Therefore, how to design and realize a noise source which works in a higher frequency band (Ka band), has high bandwidth, uniform spectral density, high output power and is easy to realize is an important task.

Disclosure of Invention

The purpose of the invention is as follows: to above problem, the utility model provides a solid-state noise source device works at the Ka wave band, has high super noise ratio, low standing wave coefficient and broadband.

The technical scheme is as follows: the technical scheme adopted by the utility model is a solid-state noise source device, including constant current source, microstrip low pass filter, noise diode, attenuator and waveguide-coaxial-microstrip converter of electricity connection in order, noise diode is used for producing original noise signal, and original noise signal passes through the noise power is stabilized to the attenuator, microstrip low pass filter arranges in noise diode's input is used for suppressing the leakage of noise power; the waveguide-coaxial-microstrip converter is used for converting the noise signal from the waveguide into microstrip output, and the output end of the waveguide-coaxial-microstrip converter is used as the output of the solid-state noise source device; the attenuator and the waveguide-coaxial-microstrip converter jointly coordinate the impedance matching of the circuit, and the constant current source provides a stable power supply for the device.

The waveguide-coaxial-microstrip converter comprises a waveguide, a first microstrip line integrated on a dielectric substrate and a coaxial line connecting the waveguide and the first microstrip line; the coaxial line comprises a probe embedded in the waveguide, a central conductor connected with the probe and an insulating sleeve wrapped outside the central conductor, wherein the probe, the central conductor and the first microstrip line are all made of copper and are welded into a whole, an air gap is reserved between the insulating sleeve and the waveguide (from the lower edge of the insulating sleeve to the upper surface of the waveguide), and the wave impedance is changed by adjusting the length of the air gap. The waveguide surface is gold plated. The radius of the central conductor is preferably 0.5 to 0.6 mm.

The microstrip low-pass filter is composed of a quarter-wavelength impedance line integrated on a medium substrate and two quarter-wavelength double-sector microstrip lines in a parallel structure, wherein the double-sector microstrip lines are connected to the middle section of the impedance line and are composed of two opposite sector branches taking the impedance line as a central axis. In order to save the space of the device and obtain a wider frequency band, the length of the microstrip low-pass filter along the direction of the impedance line is less than 5 mm. The impedance line and the double-fan-shaped microstrip line are made of copper foils, and the thickness of each copper foil is 0.01-0.02 mm.

Preferably, the solid-state noise source with the circuit structure is adopted, the attenuator is preferably a fixed gain attenuator adopting a balanced three-way thin film resistor process, and two ends of the attenuator are further provided with a blocking circuit. The model of the noise diode adopts WZ0003H series. The constant current source adopts an integrated three-terminal voltage regulator LM317 with variable output voltage as voltage-stabilizing output.

In order to control the on-off of the noise source, the device also comprises a switch driving circuit which is connected between the fixed gain attenuator and the waveguide-coaxial-microstrip converter in series and is used for controlling the on-off of the circuit. Preferably, the switch driving circuit comprises a PIN diode and a PIN diode switch driver, and the PIN diode switch driver sends a driving signal to control the on/off of the PIN diode.

Has the advantages that: compared with the prior art, the utility model, have following advantage: the utility model discloses diode WZ0003H series based on chip encapsulation combines waveguide-coaxial-microstrip converter to satisfy the requirement that the noise source work in the Ka wave band; the constant current source circuit is combined with the fixed gain attenuator to stabilize the output power of the noise source; the waveguide-coaxial-microstrip converter adopts an insulator probe transition mode, and realizes impedance matching of a circuit together with an attenuator so as to reduce power loss and reduce standing wave coefficient; the microstrip low-pass filter plays a role in preventing signal leakage, adopts double fan-shaped microstrips in structure, and improves the bandwidth; the structure of the double-fan-shaped microstrip low-pass filter can well avoid signal leakage and save space for a noise source system. Last switch type circuit structure design is convenient for control the switch of noise source in the in-service use, for being based on the utility model discloses an integrated design and relevant parameter test facilitate. The utility model provides an all circuit unit in the noise source all realize through PCB technology on the medium substrate, have higher machining precision and lower cost.

Drawings

Fig. 1 is a circuit block diagram of a solid-state noise source according to the present invention.

Fig. 2 is a schematic view of the appearance structure of the present invention.

Fig. 3 is a circuit diagram of the constant current source according to the present invention.

Fig. 4 is an internal structure diagram of the microstrip low-pass filter according to the present invention.

Fig. 5 is a diagram of the waveguide-coaxial-microstrip transition structure according to the present invention.

Fig. 6 is a standing wave coefficient test chart according to the present invention.

Fig. 7 is a real object diagram of the solid-state noise source product according to the present invention.

Detailed Description

The technical solution of the present invention will be further explained with reference to the accompanying drawings and examples.

The circuit module schematic diagram of the solid-state noise source is shown in fig. 1, the utility model provides a solid-state noise source, including WZ0003H series noise diode, constant current source circuit, microstrip low pass filter, attenuator, switch drive circuit and waveguide-coaxial-microstrip converter. The constant current source circuit supplies power to the noise diode, a noise signal generated by the noise diode has stable output power after passing through the attenuator, and the noise signal is output through the waveguide-coaxial-microstrip converter under the control of the switch of the driving circuit. Two ends of the attenuator are provided with a blocking circuit, and two blocking capacitors C1 and C2 are adopted in the embodiment.

The schematic view of the appearance structure of the utility model is shown in fig. 2. The whole component is 6.5cm long, 4cm wide and 1.2cm high, and the noise diode, the constant current source, the switch driving circuit and the matching circuit are integrated on one PCB 201. The constant current source 202 and the matching circuit are both disposed in a sealed cavity 203. In practical use, the resistor R is set to 68 Ω, the LOAD is connected with the noise diode, and the +12V voltage is connected to the Vin end 204 of the noise source metal cavity shell to provide a constant working current for the noise tube. The current actually measured by the system is 19mA, and the power supply requirement of a noise source +24V is met. In addition, the ATN3580 series 2dB fixed gain attenuator adopts a balanced three-way thin film resistor process and is integrated between the output end of the noise diode and the driving switch 205, so that the output impedance matching function is realized. The utility model discloses a PIN diode switch MA4AGSW1 control noise source's output. The noise diode is connected into the inductance-capacitance network after being externally connected with the PIN tube driver BHD-2P2 to form the switch circuit 205 to prevent signal leakage. The +/-5V power supply end 206 outside the metal cavity supplies power for the driving switch circuit, and the driving signal end 207 is connected to the integrated PCB 201 through a small hole of the shell and is connected with a pin of the driving switch chip to be externally connected with a working signal.

The utility model discloses a constant current source circuit diagram is shown in fig. 3, chooses for use the integrated three terminal regulator that the model is LM317-N, and the packing model is SOT-223(4), and whole volume is 6.5mm 3.5 mm. The LM317 integrated three-terminal voltage stabilizer can be used as an accurate constant current source by additionally arranging a fixed resistor to be connected with a load, the design is simple, and the output constant current power supply is easy to control.

The microstrip low-pass filter designed by the system is composed of a quarter-wave impedance line (inductance characteristic) and a quarter-wave parallel connection structure double-sector microstrip line (capacitance characteristic) as shown in fig. 4, and is connected between the output end of a constant current source and the input end of a noise diode. The front port 401 of the microstrip filter is connected with an external circuit (the output end of the constant current source), the middle section 402 of the impedance line is connected with two double-sector microstrip lines 403 with a parallel structure, each double-sector microstrip line 403 is composed of two opposite sector branches, and the two opposite sector branches use the impedance line as a central axis. The structure is integrated on a dielectric substrate 404 of Rogers 5880 with the thickness of 0.127mm and the dielectric constant of 2.2, the impedance lines and the double fan-shaped microstrip lines are made of copper foils, and the thickness of the copper foils is 0.017 mm. The length from the left port to the right port is 4.95mm, the frequency band is wide, and the space is saved. The noise diode-biased low-pass filter structure can suppress leakage of noise power.

Fig. 5 shows an internal structural schematic diagram of the waveguide-coaxial-microstrip converter, where impedance matching is implemented in an insulator probe transition manner, a signal enters from a port of the waveguide 501, is finally converted into a microstrip through a coaxial line, and is output by the first microstrip line 505. The first microstrip line 505 is integrated on the dielectric substrate 506 of Rogers 5880 having a dielectric constant of 2.2. The coaxial line is composed of a probe 502, a central conductor 503 and an insulating sleeve 504 which are buried in the waveguide, the central conductor 503 penetrates through a dielectric substrate 506 and is connected with a first microstrip line 505 with the impedance of 50 omega at the upper part in a welding mode, and the coaxial line has the advantages of low loss, compact structure, good sealing performance, convenience in processing and manufacturing and the like. The surface of the waveguide 501 is gold-coated, and the insulating sleeve 504 is a hollow cylinder wrapped around a central conductor 503 with a radius of 0.55mm, and has a relative dielectric constant of 4.1 and an outer radius of 0.975 mm. The probe 502, the central conductor 503 and the first microstrip line 505 are all made of copper and are welded into a whole. An air gap is left between the lower edge of the insulating sleeve 504 and the upper surface of the waveguide 501, and the length of the air gap is adjusted to change the wave impedance and reduce the standing wave coefficient.

The utility model discloses choose for use direct test method to measure the standing wave coefficient as shown in figure 6. It can be seen that the system has a standing-wave ratio of output noise at 40GHz of about 1.5: 1 in a frequency band of 25-40GHz, and has good performance in a high-frequency band.

The utility model discloses a final product picture in kind is shown in FIG. 7, and its technical indicator who reaches is as follows:

noise band of noise source output: 25-40 GHz;

super noise ratio of output noise signal: 21 +/-2 dB;

standing wave coefficient of noise source: less than 1.5: 1;

interface specification: WR-28 standard rectangular waveguide;

power supply voltage of noise source: + 24V.

It can be seen that the utility model discloses can provide up to 21 2 dB's super noise ratio and wideer frequency channel for the system, the standing wave coefficient of noise source is less than 1.5 simultaneously.

Claims

1. A solid-state noise source device is characterized by comprising a constant current source, a microstrip low-pass filter, a noise diode, an attenuator and a waveguide-coaxial-microstrip converter which are electrically connected in sequence, wherein the noise diode is used for generating an original noise signal, the original noise signal passes through the attenuator to stabilize noise power, and the microstrip low-pass filter is arranged at the input end of the noise diode and is used for inhibiting the leakage of the noise power; the waveguide-coaxial-microstrip converter is used for converting the noise signal from the waveguide into microstrip output, and the output end of the waveguide-coaxial-microstrip converter is used as the output of the solid-state noise source device; the attenuator and the waveguide-coaxial-microstrip converter jointly coordinate the impedance matching of the circuit, and the constant current source provides a stable power supply for the device.

2. The solid state noise source device of claim 1, wherein: the waveguide-coaxial-microstrip converter comprises a waveguide, a first microstrip line integrated on a dielectric substrate and a coaxial line connecting the waveguide and the first microstrip line; the coaxial line comprises a probe embedded in the waveguide, a central conductor connected with the probe and an insulating sleeve wrapped outside the central conductor, wherein the probe, the central conductor and the first microstrip line are all made of copper and are welded into a whole, an air gap is reserved between the insulating sleeve and the waveguide, and the wave impedance is changed by adjusting the length of the air gap.

3. The solid state noise source device of claim 2, wherein: the surface of the waveguide is plated with gold, and the radius of the central conductor is 0.5-0.6 mm.

4. The solid state noise source device of claim 1, wherein: the microstrip low-pass filter is composed of a quarter-wavelength impedance line integrated on a medium substrate and two quarter-wavelength double-sector microstrip lines in a parallel structure, wherein the double-sector microstrip lines are connected to the middle section of the impedance line and are composed of two opposite sector branches taking the impedance line as a central axis.

5. The solid state noise source device of claim 4, wherein: the length of the microstrip low-pass filter along the direction of the impedance line is less than 5mm, the impedance line and the double-fan-shaped microstrip line are made of copper foils, and the thickness of the copper foils is 0.01-0.02 mm.

6. The solid state noise source device of claim 1, wherein: the attenuator is a fixed gain attenuator adopting a balanced three-way thin film resistor process, and two ends of the attenuator are provided with blocking circuits.

7. The solid state noise source device of claim 1, wherein: the model of the noise diode adopts WZ0003H series.

8. The solid state noise source device of claim 1, wherein: the constant current source adopts an integrated three-terminal voltage regulator LM317 with variable output voltage as voltage-stabilizing output.

9. The solid state noise source device of any of claims 1 to 8, wherein: the device also comprises a switch driving circuit which is connected between the fixed gain attenuator and the waveguide-coaxial-microstrip converter in series and is used for controlling the on-off of the circuit.

10. The solid state noise source device of claim 9, wherein: the switch driving circuit comprises a PIN diode and a PIN diode switch driver, and the PIN diode switch driver sends a driving signal to control the connection and disconnection of the PIN diode.